Earlier this month, the Orioles traded closer Jim Johnson to the A's, largely because they were concerned his salary would top $10 million via arbitration. On Tuesday, they signed Grant Balfour to a two-year, $15 million deal, not only replacing Johnson in what was effectively a swap of closers but getting the better end of the deal.

Balfour, an Australian native who turns 36 on Dec. 30, only has one season as a full-time closer under his belt after spending his 20s battling arm and control issues while passing from the Twins to the Reds to the Brewers. Since breaking out with the Rays in 2008, however, he's been one of the game's top relievers, not to mention one of its more entertaining ones. Over that span, his 2.74 ERA ranks 10th among relievers with at least 300 innings, his 9.7 strikeouts per nine 12th. His 383 relief appearances (64 per year) rank 10th over that span, while his 9.6 WAR (Baseball-Reference.com version) is tied for eighth:

Balfour has had only one dud year in that span, when his ERA skyrockedted to 4.81 in 2009; he's been below 2.60 in the other five seasons and has been a key late-inning reliever for four playoff teams. He's spent the past three years with Oakland, working as a setup man in 2011, saving 24 games in 26 attempts in 2012 despite losing the closer job for about three months due to some early-season hiccups, and then going 38-for-41 in save tries this past season.

Balfour pitched to a 2.59 ERA and struck out 10.3 per nine in 62 2/3 innings this past season, his highest rate since 2008. That said, his 3.6 unintentional walks per nine was his highest rate since 2009 — more ball fours for Balfour — and his 1.0 homers per nine was roughly double last year's rate, and 22 percent above his career mark. His 1.4 WAR was nearly a win off his 2.3 in 2012, though for the three-year period, his 5.7 WAR still ranks ninth.

Balfour relies mainly on a mid-90s fastball (average velocity 93.8 mph in 2013) and slider against righties, substituting a curve for the slider more often than not against lefties. While his platoon splits are basically even for his career (.629 OPS allowed against righties, .616 against lefties), he's been more effective against lefties in each of the past three years, holding them to a combined .179/.255/.276 line in 408 PA in that span, compared to .196/.275/.330 in 385 PA against righties. That's still a combined .567 OPS allowed for the period, the ninth-lowest mark among pitchers with at least 150 innings across those three seasons. By comparison, Johnson ranks 29th in that span with a .629 OPS allowed.

If there's a concern, it's that the move from the spacious Oakland Coliseum and the largely pitcher-friendly AL West to Camden Yards and the more hitter-friendly AL East could be a tougher one for the flyball-heavy Balfour. Over the last three years, he has yielded a .515 OPS and 1.58 ERA at home compared to .631 and 3.78 on the road. While he did survive his previous stint in the AL East with the Rays, he had the advantage of the division's most favorable ballpark last time around, something he won't have in Baltimore.

Because he's thrown about 30 fewer innings than Johnson over the past three years (199 1/3 to 230), Balfour has been less valuable than his predecessor over that span, with 5.7 WAR to Johnson's 6.6. However, most of Johnson's advantage owes to his throwing 91 innings to Balfour's 62 back in 2011, before either was a closer. While Johnson's sinkerball-driven approach may have been the better suited of the two for Camden Yards, Balfour's 9.2 strikeouts per nine is far superior to Johnson's 6.1, making him a better bet to maintain his current level of performance.

Because he saved 101 games over the past two years, leading the AL both times, Johnson is expected to earn at least $10 million via arbitration, a figure that general manager Dan Duquette judged too rich for the Orioles' tight payroll, and one that's out of step with the industry. As I noted when Brian Wilson re-signed with the Dodgers, while relievers have previously received a total of 24 deals worth more than $7 million per year, only those of Rafael Soriano ($14 million per year), Jonathan Papelbon ($12.5 million per year), Joe Nathan ($10 million per year), Wilson ($9.25 million per year including his 2015 player option) and Heath Bell ($9 million per year) are currently in effect. Balfour's deal joins that group, but $500,000 from each season will be deferred, lowering the present-day value of the contract slightly.

In all, the Orioles are paying one of the game's top 10 relievers a top 10 salary, albeit one toward the lower end of that scale, and considerably less than they would have been paying their former closer. It's possible that the move could backfire if age catches up to Balfour or if he doesn't take to Camden Yards, but his salary is reasonable enough that he could still be moved if the latter is a problem. In all, this is a pretty decent deal for Duquette and company.